2duh
crystal structure of a green fluorescent protein variant S65T/H148N at pH 9.5crystal structure of a green fluorescent protein variant S65T/H148N at pH 9.5
Structural highlights
Function[GFP_AEQVI] Energy-transfer acceptor. Its role is to transduce the blue chemiluminescence of the protein aequorin into green fluorescent light by energy transfer. Fluoresces in vivo upon receiving energy from the Ca(2+)-activated photoprotein aequorin. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedWild type green fluorescent protein (wt-GFP) and the variant S65T/H148D each exhibit two absorption bands, A and B, which are associated with the protonated and deprotonated chromophores, respectively. Excitation of either band leads to green emission. In wt-GFP, excitation of band A ( approximately 395 nm) leads to green emission with a rise time of 10-15 ps, due to excited-state proton transfer (ESPT) from the chromophore hydroxyl group to an acceptor. This process produces an anionic excited-state intermediate I* that subsequently emits a green photon. In the variant S65T/H148D, the A band absorbance maximum is red-shifted to approximately 415 nm, and as detailed in the accompanying papers, when the A band is excited, green fluorescence appears with a rise time shorter than the instrument time resolution ( approximately 170 fs). On the basis of the steady-state spectroscopy and high-resolution crystal structures of several variants described herein, it is proposed that in S65T/H148D, the red shift of absorption band A and the ultrafast appearance of green fluorescence upon excitation of band A are due to a very short (<or=2.4 A), and possibly low-barrier, hydrogen bond between the chromophore hydroxyl and introduced Asp148. Ultrafast excited-state dynamics in the green fluorescent protein variant S65T/H148D. 1. Mutagenesis and structural studies.,Shu X, Kallio K, Shi X, Abbyad P, Kanchanawong P, Childs W, Boxer SG, Remington SJ Biochemistry. 2007 Oct 30;46(43):12005-13. Epub 2007 Oct 6. PMID:17918959[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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